Isolation of community-acquired methicillin-resistant Staphylococcus aureus in healthy carriers in a Mexican community

Summary Objectives Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) clones are spreading rapidly among the population in many regions worldwide. Little information is available on CA-MRSA in Mexico. The aim of this study was to identify CA-MRSA strains in the nose and throat of healthy people in a Mexican community. Methods A total of 131 MRSA strains from the nose and throat obtained from healthy people in Mexico City were characterized. The genes mecA , lukS-PV/lukF-PV , and ACME- arcA were detected by PCR. Staphylococcal cassette chromosome mec (SCC mec ), pulsed-field gel electrophoresis (PFGE), and spa typing were performed. Results Bacteria that had a Panton–Valentine leukocidin (PVL)-positive gene and SCC mec type IV or V were designated as CA-MRSA strains. We found that 21.4% of MRSA strains were CA-MRSA and that the percentage of CA-MRSA strains was similar in the nose and the throat. A great diversity of profiles was found in the strains identified by PFGE pattern and spa typing. Only one strain similar to the USA300 genotype was found; this strain carried the ACME- arcA gene. Conclusions CA-MRSA strains were detected in the nose and throat of healthy people. We identified a high level of genetic diversity among CA-MRSA strains in healthy people of Mexico City, which were different from the USA and pandemic clone profiles.